Telegraph switching system



Jan. 7, 1947.

w. R. YOUNG, JR

TELEGRAPH SWITCHING SYSTEM Filed Nov. 19, 1942 5 Sheets-Sheet 1IIEVHOARD PRFOR4 TOR FIG 4- FIG. 2 FIG. 3

INVENTOF? W R YOUNG JR 7 ATT'QRNEY,

Jan. 7, 1947. w. R. YOUNG, JR

TELEGRAPH SWITCHING SYSTEM Filed Nov. 19, 1942 5 Sheets-Sheet 2 -21 EE21 N in? m Q s A TTOQNE V Jan. 7, 1947. w. R. YOUNG, JR

TELEGRAPH SWITCHING SYSTEM Fi led Nov. 19, 1942 5 Sheets-Sheet 5 E u u AT TO RNE 1 Jan. 7, 1947.

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CONTACTS 0F 6 6M 1 &

REFINl/ILG PROCESS 7- a) CONDENSER um R655 w. RQYOUNG, JR

TELEGRAPH SWITCHING SYSTEM 5 Sheets-Sheet 5 sra; START N0.l NQZ Mas N04N05 STOP J I I r I I I I I I I I l l I I I I l I I I l I I F I I l l I JI I I I l IZ'Z'KZ}! viva I I I l WWW I A I V l I I I I I I 1 I- I I ZI\CHARGE$ 01v I CONDENSERS l I APPLIED AT I I 1 THIS INSTANT I I To ICHARACTER- 'W A new GN/ZING I cmcu/r I l zumo ,x f I I I I I I I JW A481/ I I -.4av I I I I u I I 48V I I I I l lNl/E N TOR ATTORNEV PatentedJan. 7, 1947 2,413,741 TELEGRAPH SWITCHING SYSTEM William R. Young, Jr.,Summit, N.

Bell Telephone Laboratories,

J assignor to Incorporated,

New York, N. Y.,, a corporation of New York Application November 19,1942, Serial No. 466,127

7 Claims.

This invention relates to distributor system in which a succession ofgroups of impulses including a start impulse, code conditions, each ofwhich may be of one or the other of two kinds such as marking andspacing, and a stop pulse are distributed and accurately formed andtimed without the use of rotary or power driven machinery.

An object of the invention is to substitute relay systems for motor orotherwise driven rotating elements, such as rotary distributors, forscanning and correcting the shape of transmitted and/or receivedpermutation code signals.

As embodiments of the present invention, two exemplary forms of circuitarrangements are disclosed; using similar principles for sending orreceiving device permutation code or teletypewriter signals. These unitsare disclosed by Way of illustration at the sending and receivingtermini of a channel of transmission.

The sending unit is designed to generate, shape, time and transmitteletypewriter signals in which the code pulses of each character signalare determined by simultaneously set combinations of code conditionssuch as might be set up by a teletypewriter keyboard or tapetransmitter, or relays, etc.

The receiving unit is designed to receive teletypewriter signalsconsisting of code combinations of impulses arriving in time sequence,distribute and start the code pulses for selective recognition of aparticular code combination to control the operation of a particulardevice or relay, or combination of relays. The device or relay thuscontrolled may control a director circuit for selecting, testing orconditioning a line or channel or may be extended through fanning-outrelays such as disclosed in a patent to Krecek 2,368,666, datedFebruaryfi, 1945, or used to control transmitters or receivers as inpatent to Krecek et al., 2,366,733, dated January 9, 1945, or it mayconstitute the ultimate element to be selected. In each of these unitsthe desired results are accomplished without the use of brush type orcam type rotating distributors.

A feature of the invention is (1) a sending unit suitable fortransmission from group settings of code contacts such as may be set bya keyboard, tape-feeler-pass, relays etc., and (2) a receivin unit toreceive and distribute permutation code signals remotely transmittedfrom teletypewriter tape or keyboard and make selections under controlthereof.

Another feature is the provision of a circuit arrangement wherein thereis a continual readiness feeler pins of a tape to send and/ or receive,and no wear is occasioned during the idle, or waiting, periods.

Another feature is the economy effected in the use of relays in place ofrotary distributors.

Another feature is the use of scanning operation in both units and thedividing of such operation in each case into two parts, namely, a roughscanning process and a refining process.

The foregoing objects, features and operation for the specificembodiments of the invention, the novel features of which arespecifically pointed out in claims appended hereto, may be more fullyunderstood from the following description when read with reference tothe attached drawings in which: 1

Figs. 1 and 2 show the sending unit at the originating end of ateletypewriter switching system;

Fig. 3 shows the receiving unit at the terminating end of ateletypewriter switching system;

Fig. 4 shows the relative arrangement of Figs. 1, 2 and 3;

Fig. 5 illustrates by a series of curves the principles of operation ofthe sending unit; and

Fig. 6 illustrates by a series of curves, the principles of operation ofthe circuit of the receiving unit.

The use of reference characters shown on Figs. 1, 2 and 3 have been keptto a rigid plan. Thus all relays shown in each of Figs. 2 and 3 havereference characters consisting of numerals and letters, the numeralsshown are prefixes corresponding to the figure in which the particularrelay is located. All other parts of the circuit are designated bynumerals only, for instance, those parts of Fig. 1 are designated withnumerals between IOO and I99, those of Fig. 2 are designated withnumerals between 200 and 299, etc., wherein the hundreds digitdesignates the figure in which the particular part is found.

Sending unit, Figs. 1 and 2 The system shown in the drawings is arrangedfor transmitting permutation code signals from a tape transmitter at thesending station to an arrangement at a receiving station. Especiallydesigned devices'employing substantially the same principles areemployed at opposite ends of the transmission circuit. However, it isnot necessary that these devices be provided at opposite ends of asingle transmission circuit. It may be preferable to provide a systemwherein a specially designed device is used at one end only of thetransmission circuit.

In the drawings of the present application, there is shown forillustrative purposes only, a

3 teletypewriter system having a specially designed device at each endof a transmission circuit.

The medium for transmitting permutation code signals in the illustratedembodiment of the invention consists of a keyboard perforator IOI,perforated tape I02 and a tape transmitter I03. The tape transmitter isdriven by motor I04 which receives its operating current from alterhaticurrent source I05. When there is a sufficient supply of tape perforatedfor message sending purposes, contacts I06 are closed and.

maintained energized the operating circuit for relay I01 from sourceI05. Manually operated switches I08 and I09 are provided to open, asdesired, the operating circuit for motor I04 and the operating circuitof relay I01, respectively. During transmission by the keyboardtransmitter, contacts I06 are closed, motor I04 is operating and relay I01 is in its operated position unless the supply of perforated tape isdepleted at which time tape I02 becomes taut and thereby raises arm I Ito open contacts I06. When contacts I06 open transmission stops untilsuflicient the perforated tape accumulates to permit contacts I06 toclose. A suitable device for automatically .opening contacts I06 isdisclosed in Dixons which employs relay 2A, 2B, 2C, 2D, 2E, 2F, 2G.

and 2H and the other, the refining process which employs, in the main,relay 2L, 2J, and 2K of an oscillating circuit. The rough scanningproduces signal pulses of approximately equal lengths and the refiningprocess signals of exactly equal unit lengths.

In the idle condition, relay 2H is operated by its locking circuit whichis traceable from grounded battery, through the winding, No. 2

armature and front contact of relay 2H, lefthand contact AK and armatureof relay 2K, to

ground. Relay 2H, in its operated position, provides a current forholding relay 2M normally operated in a circuit traceable from groundedpositive 43-volt battery 20l, front contact and armature No. of relay2H, through the upper winding of relay 2M, to ground. Relay 2M, in itsnormally operated position, holds itself in readiness to produceoscillations, the circuit being traceable from grounded negative 48-voltbattery 202, left-hand, or marking, contact and armature of relay 2M,condenser 203, to ground.

At the beginning of a transmission period, switches I08 and I 09 areoperated to the positions shown and as soon as sufiicient tape isperforated atperforator I 0| the slack thereby produced in tape I02permits the closure of contacts I06. Relay I01 operates to close acircuit that may be traced from grounded negative 48-volt battery II I,conductor I I2, through the lower winding of relay 2M, to ground, andrelay 2M operates to its right-hand, or spacing, contact. Relay 2M, uponoperating to its spacing position, causes condenser 203 to discharge ina circuit traceable over the armature and right-hand, or'spacing,contact of sh m i i and AL, respectively by means of another circuittraceable from grounded negative 48-volt battery 206, contact BJ andarmature of relay 2J, through the windings, in parallel, of relays 2J,2K and 2L, retardation coil 204, right-hand, or spacing, contact andarmatures of relay 2M, condenser 203, to ground. Condenser 203 ischarged to a potential having a value approximating that of groundednegative 48-volt battery 206 which is of the same voltage as that ofgrounded negative battery 202. Relay 2J, returning to its contact AJ,closes a circuit hereinbefore traced, for again discharging condenser203, and the armatures of relays 2J, 2K and 2L again operate to theircontacts BJ, BK and BL, respectively, after the discharge currentbecomes zero and reverses. This oscillation continues in the mannerhereinbefore described because of the excitation furnished by the.appropriate operation of the armature of relay 2J between contacts AJand BJ.

The normally closed signaling circuit, or loop, is traced from thepositive pole of battery 207, conductors 208, 209 and 2l0, contact andupper armature of relay 2H, conductor 2| I, contact AL and armature ofrelay 2L, conductor 2I2, through the upper windings, in series, ofrelays 3K and 3L, conductor 30I, to the negative pole of battery 201. Aquarter of a cycle after the start of the oscillations, the'closure ofthe signaling circuit is opened by the operation of relay 2L to aposition wherein the relay armature engages contact BL. The opencondition of the signaling circuit is maintained for the duration of aunit pulse to send a start, or spacing, pulse to the receiving station.

Also, at this time relay 2K operates to contact BK and thereby unlockrelay 2H which now releases. Relay 2H, upon releasing, closes a circuittraceable from grounded negative 48-volt "battery 2I3, through the upperwinding of relay 2M and thereby reverses the current flowing in thisupper winding to maintain relay 2M in its spacing position for theduration of the code combination for the character or function signalthat is being transmitted over the signaling circuit. Also, relay 2H,upon releasing, closes at its N0. 4 armature and contact an operatingcircuit for relay H8 which operates and thereby permits cam shaft I I9to rotate under the influence of friction clutch I2I to start the tapetransmitter I03 operating, retract the sensing pins, step the tape andoperate the sensing pins to sense the next code combination punched inthe tape.

Relay 2K, upon operating to its contact BK,

. had also closed an operating circuit for relay 2A,

the circuit being traceable from ground at the armature and contact BKof relay 2K, outer lower armature and back contact of each of relays 2F,2D and 2B, in turn, through the winding of relay 2A, to grounded batteryand relay 2A operates. Relay 2A, upon operating, locks in a circuittraceable over its inner lower armature and contact,

make-before-break contacts of each of relays 20,

2E and 2G, inturn. to ground at the normally 'open make-before-breakcontact 2I4.

mitter lea Relay 2K, upon operating back to contact AK in its course ofoscillating, closes an operating circuit-for relay 2B, the circuit beingtraceable from ground at contact AK of relay 2K, makebefore-breakcontact 2l5, outer lower armature and back contact of each of relays 2G,2E and 20, in turn, outer lower armature and front contact of relay 2A,through the winding of relay 23, to grounded battery, and relay 2Boperates thereby opening the operating circuit for relay 2A which,however, remains in its operated condition due to its locking circuit.

Relay 23, upon operating, looks over a part of the locking circuit usedfor relay 2A which was hereinbefore traced.

RelayZK, upon operatingagain to contact BK due to its oscillatingcircuit, closes an operating circuit for relay 20 which operates, theoperating circuit being similar to that of relay 2A except that it nowextends over the outer lower armature and front contact of relay 2B,through the winding of relay 2C. Relay 20, upon operating, looks overpart of the locking circuit used for relays 2A and 2B, except that theinner lower armature and front contact of relay 2C is now included.Also, relay 20, upon operating, opens at its inner lower armature andcontact, the looking circuit for relay 2A which now releases.

Likewise, relays 2D, 2E, 2F and 2G, in turn, are operated and locked intheir operated positions during the operation of the oscillatingcircuit, and each relay except relay G, in turn, is released when itssecond succeeding relay is'operate'cl, for example, relay A releaseswhen relay 20 operates, relay 2}; releases when relay 2D operates, etc.Relay G, upon cperating,'locks in its operated condition over a circuitdirectly traceable to ground at contact 2M of relay 2H in it releasedposition, and its locking circuit is opened when relay 2H operates atthe end of each character signal.

Assume that the first character signal transmitted is the letter S, thenthe corresponding pulses in permutation code are marking, spacing,

marking, spacing and spacing for the selective pulses, the start pulseas hereinbefore stated being spacing and the stop pulse being marking.Accordingly, contacts I and 3 of tape transare closed and contacts 2, Aand 5 are to the time that the start, or spacing, pulse is transmittedover the signaling circuit, the path prepared thereby over whichthefirst selective pulse which is marking is transmitted, finds relay 2Loperated to its contact AL,

open. To go back relay 2H released, relay 2A operated and contacts No. lof the tape transmitter I03 closed in accordance with the permutationcode combination ior letter S. The circuit for transmitting the first,or marking, pulse, which is now completed,

extends from the positive pole of battery 26?,

conductor 29%, No. '1 contact of tape transmitter m3, conductorll3,'contact and upper armature of relay 2A, conductor 2| l, contact ALand armature or relay 2L, conductor 212, through the upper windings, inseries, of relay-s 3K and 3L, conductor SiiL'to the negative pole ofbattery Mill. The first pulse is therefore transmitted at the correctinstant by the operation of the armature of relay 2L to contact AL, andthe completed circuit is then opened at the correct moment by the returnof the relay armature to contact BL.

' In the meantime relay 2B has operated and inasmuch as contact No. 2 oftape transmitter I- IE3 is open in this permutation code combination andrelay 21-1 is released, the second selective, or

spacing, pulse i E5 transmitted over the signaling circuit at the timethat the armature of relay 2L is in engagement with the contact BL.

The oscillating circuit in its course of operating, next moves thearmature of relay 2L back to its contact AL and inasmuch as contact No.3 of the tape transmitter is closed and relay 2C is operated at thistime, the signal circuit is closed a hereinbefore traced except that itnow extends over contact No. 3 of the tape transmitter, conductor i l5,contact and armature of relay 2G to conductor 2i l. A marking pulse istherefore transmitted to the receiving station.

The next operation of the oscillating circuit moves the armature ofrelay 2L into engagement with the contacts BL and inasmuch as contactNo. 4 of the tape transmitter is open and relay 2-H is released, an openpulse, that is a spacing pulse is transmitted over the signal circuit.

Likewise contact No. 5 of the tape transmitter is open and relay 21-1 isreleased as the oscillating circuit again moved the armature of relay 2Lback to contact AL and an open pulse, that a spacing pulse, istransmitted to the receiving circuit.

When relay 2L operates to move its armature into engagement with contactBL, to terminate the transmission of 2F is in an operated position andthe signaling circuit is again closed and now includes conductors resand tea, contacts and armature of relay and contact BL and armature ofrelay 2Lto send the stop, or marking, pulse. When relay EL moves itsarmature back to contact AL and relay 2G is in its operated position,the signaling circuit is maintained closed to maintain the stop pulse asmarking. The circuit now includes conductors 2M and 2m, contact andupper armature of relay 2G, conductor 2!! and contact AL in engagementwith the armature of relay 2L.

Relay 2K which operate in synchronism with relay 2L in the oscillatingcircuit, moves its armature into engagement with contact AK at the sametime that relay 2L moves its armature into engagement with contact ALand a circuit is therefore closed extending from ground at the armatureand contact AK of relay 2K, makebefore-break contacts 2E5, outer lowerarmature and front contact of relay 2G, through the winding of relay21-1, to grounded battery. Relay 2H again operates and locks in itsoperated position in a circuit traceable over its No. 2 armature andcontact to ground at contact AK and armature of relay :ZK. Relay 2H,upon operating, also transfers its armature No. 5 from its back contactto its front contact and thereby reversing the current flow in the upperwinding of relay 2M. This causes relay 2M to operate to its left-hand,or marking, position, if the current in the lower winding of relay 2Mhas become zero because of open contacts at relay lull. Relay 2M, in itsmarking position, stops the oscillating circuit and restores thetransmitting arrangement to its normal, or idle, condition in readinessto send a new signal character. If relay 2M has remained in its spacingposition the oscillating circuit continues and the sending of the nextcharacter or function code combination the selective pulses, relaycross-hatched section "the start-stop permutation code signalcombination representing the letter S which is assumed herein as beingthe first signal prepared on the perforated tape for transmission by thetape transmitter I03. The stop and start signals are, as usual, shown tobe marking and spacing respectively, and the five selective pulses ofthe signal combination are shown marking, spacing, marking, spacing andspacing. At th instant relay I01 operates spacing current begins to flowin the lower winding of relay 2M from grounded negative 48-volt batteryII I and this current is in opposition to the marking current normallyfiOWing in the upper winding of relay 2M from grounded positiv 48-voltbattery I. The spacing current in the lower winding is of sufiicientmagnitude to overcome the marking current in the upper winding andthereby causes relay 2M to move its armature to its spacing contact.Relay 2M, upon operating, as hereinbefore stated,

starts the oscillating circuit and th normally operated relay 2H therebyreleases. Relay 2H, upon releasing, disconnects grounded positive 48-volt battery 20I and connects in its place grounded negative LS-voltbattery 2I3 to the upper winding of relay 2M. The current flowing in theupper winding of relay 2M, due to the release of relay 21-1 is now inthe same direction as that in the lower winding and relay 2M is held inits spacing position for the duration of transmission of the signalcombination. The currents flowing in the windings of relay 2M indicatedin curve 2S give rise to ampere-turns around the armature which areindicated in curve 2-S. Th solid lines represent the case in which theoperating circuit for relay I01 is opened, either at contacts I06 orswitch I09, during transmission of a character, while the dotted linesrepresent the case where such circuit remains closed.

Curve 3-8 shows the position of the armature of relay 2M with respect toits associated spacing and marking contacts during the time that currentis flowing in either .or both of the relay windings.

Curve lS shows the nature of the current flowing in the winding of relay2J, ZKand 2L of the oscillating circuit during the interval beginningwith the closure of the armature of relay 2M with its spacing contactand ending condenser 203 is charging and discharging in regularintervals. The relays operate simultaneously and therefore theirarmatures will be on corresponding contacts at the same instant.

Curve Ii-S shows the duration of the operation of each of relays 2A, 2B,2C, 2D, 2E, 2F and 2G during the time that a signal combination is beingtransmitted. Relay 2H which is normally operated, is in a releasedcondition during transmission of each signal combination. These relaysperform, as hereinbefore stated, the rough scanning of the signalcombination being transmitted and the refining process is performed byrelay 2L as part of the oscillating circuit. The of each blockrepresenting CPI .208, contact No, 3

the duration of operation of relays 2A, 2B, 2C,

2D,,2E, 2F and 2G is that part of the pulse that is actually transmittedover the signaling circuit by the operating armature of relay 2L. The

signal combination as impressed on the signal circuit is a wave havingpulses of uniform length and squared-topped shape as shown in curve 1-8.

The condition of the signal circuit for each pulse of a signalcombination transmitted is represented by curve 1 -S, 1 -8 and 1 -8.Normally, relays 2H and 2L are held in the positions shown and thereforeduring the stop interval of a signal combination, the armature No. 1 ofrelay 2H is in engagement With its contact, and the armature of relay 2Lis held in engagement with its contact AL. The signaling circuit, whenidle, is closed as indicated in the stop section of curves 1 --S, 1 -S,1 -5, and extends as hereinbefore traced from the positive pole ofbattery 201, conductors 208, 209 and 2I0, contact and armature No. 1 ofrelay 2H, conductor 2, contact AL and armature of relay 2L, conductor2I2, through the windings, in series, of relays 3K and 3L, and back overconductor 30I to the negative pole of battery 20'! as indicated in thefirst, or stop, section of curves 1 S, 1 S and 1 Duringthe "start pulseinterval as indicated in the second or, start, section of curves "I -S,1 -8 and 1 -3, the signaling circuit is in a spacing condition becausethe armature of relay 2L is in engagement with its contact BL and itscontact AL is open.

During the first selective pulse interval as indicated in the thirdsection, designated No. 1, of curve 1 -S, 1 -3, and 1 S, the armature ofrelay 2L is on its contact AL, the upper armature of relay 2A is closedto its contact and contact No. 1 of tape transmitter I03 is closed toplace the signaling circuit in a marking condition. The circuit nowextends from the positive pole of battery 201, conductor 208, contactNo. 1 of tape transmitter I03, conductor H3, contact and upper armatureof relay 2A, conductor 2I I, contact AL and armature of relay 2L,conductor 2I2, back over conductor ill, to the negative pole of battery201,

During the second selective pulse interval as indicated in the fourthsection, designated No. 2, of curve 1 S, 1 S, and 1 S, the armature ofrelay 2L is on its contact BL, the upper armature and contact of relay2B are closed, but contact No, 2 of tape transmitter I03 is open, toplace the signaling circuit in a spacing condition.

During the third selective pulse interval as indicated in the fifthsection, designated No. 3, of curve 1 S, l -S and 1 S, the armature ofrelay 2L is in engagement with the contact AL, the upper armature andcontacts of relay 2C are closed and contact No. 3 of tap transmitter I03is closed, to place the signaling circuit in a markat this time extendsfrom the positive pole of battery 201, conductor of tape transmitterI03, conductor II5, upper armature and contact of relay 3C, conductor 2II, contact AL and armature of relay 2L, over theloop and back to thenegative pole of battery 201. 7

During the fourth selective pulse interval indicated in the sixthsection, designated No. 4, of curves 1 -8, 1 S and 1 S, the armature ofrelay 2L is in engagement with its contact BL, the upper armature andcontact of relay 2D, are closed, but the No. 4 contact of tapetransmitter 9 N13 is open to place thesignaling circuit in a spacingcondition.

During the fifth selective pulse interval indicated in the seventhsection, designated No. 5, of curves l -S, 1 -8 and 7 -8, the armatureof relay 2L is in engagement with th contacts AL, the upper armature andcontacts of relay 2E are closed, but contact No. 5 of tape transmitterW3 is open to maintain the signaling circuit in a spacing condition.

During the first part of the stop pulse interval indicated in the stopsection of curves l -S, 'P-S and l -S, the armature of relay 2L is inengagement with contact BL, and the upper armature and contact of relay2F are closed, to place the signaling circuit in a marking condition.The signaling circuit is traceable from the positive pole of battery201, conductors 268 and 209, upper armature and contact af relay 2F,conductor 2H5, contact BL and armature of relay 2L over the loop andback to the negative pole of battery 201.

When the armature of relay 2L operates to contact AL the stop pulse iscontinued through this contact and the upper armature and contact ofrelay 2G, until relay 2H operates and relay 2G releases, whereupon theupper armature and contact of relay 2H maintain the loop closure.

Until the start of another signal combination is transmitted the stoppulse is maintained as indicated in the next section of curves l' S, 'P8and l -S.' The armature of relay 2L is held in engagement with contactAL, and the upper armature and contact of relay 2H are closed tomaintain marking condition. The signal circuit is now traceable from thepositive pole of battery 2M, conductors 2%, 299 and 2" contact and upperarmature of relay 2H, contact AL and armature of relay 2L, over the loopand back to the negative pole of battery 287. 7

Receiving unit, Fig. 3

The signal pulses during transmission over a long circuit are subject toconsiderable attenuation and therefore correcting processes, similar tothose employed at the sending end, are used at the receiving station. Atthe receiving station, the rough scanning process employ relays 3A, 3B,3C, 3D, 3E and SF and the oscillating circuit which performs therefining process comprises relays BJ, 3H and 3G. Relays 3L and 3K areprovided to receive the signal pulses incoming over the loop, or signal,circuit.

In the idle condition, that is, in the stop, or continuous marking,interval preceding a character, or permutation code, signal, relay 3F isoperated and locked in its operated position by current in a circuittraceable from grounded battery,

through the winding, inner lower armature and contact of relay 3F,left-hand contact AH and armature of relay Bl-lto ground. Although thebiasing current in the lower winding of each of relays 3L and 23K isspacing, the armatures of the respective relays are held on theirleft-hand, or marking, contacts, by the marking current in the loop, orsignaling circuit. Relay 3K, in its marking condition, holds inreadiness a path for starting the oscillating circuit, the path beingtraceable from grounded iii-volt negative battery 382, marking contactand armature of relay 3K, condenser 363, to ground, Condenser 303 istherefore held charged to a potential approximating the potential orbattery 392 when the receiving circuit is in its idle condition.

the signaling circuit in a In response to the start, or spacing, pulseof an incoming permutation code signal, the armatures of relays 3L and3K operate to their respectively associated right hand, or spacing,contacts and thereby start the simultaneous performance of both therough scanning and the refining process. Relay 3K, upon operating to itsspacing position, closes a circuit for discharging condenser 303, thecircuit being traceable from ground, condenser 3B3, resistance 3B4,retardation coil 3%, .through the windings, in parallel, of relays 3J,3H and 3G, armature and lefthand contact AG of relay 3G to ground. Thedischarging current causes the armatures of relays 3J, 3H and 3G tosimultaneously operate to contacts BJ, BH and BG, respectively.

' As soon as the charging current of condenser 303 becomes zero and thenreverses, relays 3.1, 3H and 3G return to their respective originalpositions, namely, contacts AJ, AH and AG, respectively, by means of acurrent circuit traceable from grounded negative 4=8-vo1t battery 306,contact BG and armature of relay 3G, through the windings, in parallel,of relays 3J, 3H and 3G, retardation coil 3B5, right-hand, or spacing,contact and armature of relay 3K, condenser 383 to ground. Condenser 3%again charges to a potential approximatin that of grounded negativebattery 566 which is of the same voltage as that of grounded negativebattery 302. Relay 3G, upon returning to its contact AG in response tothe charging current flowing from battery 386, closes a circuithereinbefore traced for again discharging the condenser 303 to cause thearmatures of relays SJ, 3H and 3G to again operate to contacts BJ, BHand BK, respectively. This oscillation continues in the mannerhereinbefore described because of the excitation furnished by theappropriate operation of the armature of relay 2J between its contactsAJ and BJ.

As soon as the armature of relay 3H leaves its contact AH at the startof an incoming permutation code signal received over the signalingcircuit, the locking circuit for relay 3F is opened to release relay 3F.Relay 3F, upon releasing, closes at its outer lower armature and contacta shunt path around resistance 38? whereby the biasing current flowingthrough the lower winding of relay 3K is increased to hold the armatureof relay 3K in engagement with its right-hand, or spacing, contact forthe duration of the incoming five selective pulses of the permutationcode signal.

As soon as the armature of relay 3H engages its contact BH, in themiddle of the start pulse of the incoming permutation code signal, relay3A operates in a circuit traceable from ground at the armature ofcontact BH of relay 3H, make-before-breal: contact 3538 of relay 3E,outer lower armature and back contact of relay 3D, make-before-breakcontact 389 of relay 3C, outer lower armature and back contact of relay33, through the winding of relay 3A, to grounded battery. Relay 3A, uponoperating, (1) closes at its upper armature and front contact a circuitfor charging condenser 3H), (2) locks itself at its inner lower armatureand front contact in a circuit which extends over the make-beforebreakcontacts tit, Sit, 3H and 318, in turn, of relays 3B, 3C, 3D and 313,respectively, closed contacts 319 of relay 31'", to ground, and (3)prepares at its outer lower armature and contact an operating circuitfor relay 3B which operates as hereinbefore described when the armatureof relay 3H returns to its AH contact during the 11 second cycle ofoscillations for each signal combination.

The circuit for charging condenser 3H] may be traced over the upperarmature and front contact of relay 3A, conductor 323, contact BJ andthe armature of relay 3J, resistance 32L armature and right-hand, orspacing, contact of relay 3L, to grounded negative 48-volt battery 324,and condenser 3H] thereby assumes a potential approximating that ofgrounded battery 324. Relay 3L is arranged, as hereinbefore stated, tofollow the pulses of the permutation code signals incoming over thesignaling circuit. During the first half of the first selective pulse ofthe incoming permutation code signal, condenser 3H1 will acquire avoltage representative of the marking or spacing nature of this pulse inthe signal received.

Inasmuch as letter "8 is hereinbefore selected to be the permutationcode signal transmitted from the sending station, the first selectivepulse after the start pulse, is marking and the armature of relay 3L ison its left-hand, or marking, contact. Therefore the charge impressed bythe first selective pulse on condenser 3!!) is of zero value. In themiddle of the first selective pulse further change in potential oncondenser 310 is prevented by the opening of the charging circuit whenthe armature of relay 3J returns to its contact AJ.

Relay 3H, upon operating in the oscillating circuit, causes its armatureto engage contacts AH and BH alternately at regular intervals. Relay 3H,upon moving its armature to its contact BH, operates relay 3A ashereinbefore stated, and upon causing its armature to return to contactAH closes an operating circuit for relay 2B, the circuit being traceablefrom ground at the armature and. contact AH of relay H, contact 322,outer lower armature and back contact of relay 3E, make-before-breakcontact 323, outer lower armature and back contact of relay 30, frontcontact and armature of relay 3A, through the winding of relay 3B, togrounded battery. Relay 33 operates and locks in its operated positionover its inner lower armature and front contact and part of the lockingcircuit for relay 3A hereinbefore described.

Relay 3H, upon moving its armature to contact BI-I for the second time,closes an operating circuit for relay 30, the circuit being traceablefrom ground on the armature and contact BH of relay 3H,make-before-break contact 308, outer lower armature and back contact ofrelay 3D, make-before-break contact 309, outer lower armature and frontcontact of relay 3B, through the winding of relay 3G, to groundedbattery. Relay 30 operates and locks over its inner lower armature andfront contact and part of the locking path for relay 3A.

Relay 3H, upon returning its armature to contact AH for the second time,closes an operating circuit for relay 3D, which circuit may be tracedfrom ground on the armature and contact AH of relay 3H, contacts 322,outer lower armature and back contact of relay 3E, make-before-breakcontact 323, outer lower armature and front contact of relay 30, throughthe winding of relay 3D, to grounded battery. Relay 3D operates andlocks up in a circuit traceable over its inner lower armature and frontcontact and part of the locking path for relay 3A.

Relay 3H, upon operating its armature to its contact RH for the secondtime, closes an operating circuit for relay 3E, the circuit beingtraceable from ground at the armature. and. conta t BH of relay 3H,make-before-break contact 308, outer lower armature and front contact ofrelay 3D, through the winding of relay 3E, to grounded battery. Relay 3Eoperates and locks in a circuit traceable over its inner lower armatureand front contact as part of the locking path of relay 3A.

Relay 3H, upon returning its armature to its contact AH for the thirdand last time of the group of five selective pulses representing theincoming signal for letter S, closes a circuit for reoperating relay 3Fto its normally operated position to await the next incoming signalcombination. The operating circuit for relay 3F may be traced fromground at the armature and contact AH of relay 3H, closed contact 322,outer lower armature and front contact of relay 3E, through the windingof relay 3F, to grounded battery. Relay 3F operates and locks up overits in ner lower armature and contact to ground at contact AH and thearmature of relay 3A. The looking circuit for each of relays 3A, 3B, 3C,3D and 3E is maintained closed only until the next succeeding relay isoperated, for example, relay 3A is locked in its operated position untilrelay 33 operates, likewise, 33 until relay 30 operates and so on untilrelay 3F operates and locks in its onerated position. Relay 3F, uponoperating, closes at its upper armature and contact an operating circuitfor relay 3M which operates to complete means for selecting thecharacter-recognizing equipment as will be hereinafter described. Relay3F remains operated until another signal is received over the signalingcircuit.

The operation of relays 33 to 3E in conjunction with the operation ofrelay 3J and positioning of relay 3L by incoming code pulses causescharges to be stored on condensers 3| It 0 3M, respectively, the initialmagnitudes of the charges being either zero or approximately the fullnegative value determined by the voltage of grounded negative 48- voltbattery 324. These stored charges are respectively determined by thenature of the five selective pulses constituting the incomingpermutation code signal. Charging of each of these condensers isinterrupted in the middle of the pulse which each condenser represents,by the operation of the armature of relay 3J between contacts AJ and BJ.

Shortly after the middle, viz., at the end of the fifth pulse, chargeson the code storing condensers 3H1 to 3| 4 and on condenser 325 areapplied by the operation of relay 3M, which operates in response to theoperation of relay 3F, to the winding of a character-recognizingcircuit. The character-recognizing circuit may take a variety of forms,for example, the code storing condensers in cooperation with theresistances of various values, may cause in such character-recognizingcircuit the operation of code storing relays, such as relays 3N, 3V,etc., which, in turn, may operate a set of so-called fanning relaysshown and described in Krecek Patent No. 2,368,666, supra.

With the illustration selected herein, relays 3N and 3V, respectivelyoperate in response to different permutation code signals received overthe signaling circuit, that is, relay 3N is operated for one letter, sayletter -S, and relay 3V for another letter. Each of these relaystogether with each of several other relays that may be used, isconnected so as to operate only when the desired character or letter, iselectrically stored in the code storing condensers. Relay 3N may beassumed to respond to the signal combination corresponding in a commonlyused code to letter S 13. in which case the selecting voltages furnishedby condensers 3H0 to 3M over armatures I to 5, respectively, of. relay3M are zero, -48 volts, zero, 48 volts, and 48 volts. The selectingvoltages correspond to the five selective pulses for letter S,, thepulses received, from signaling circuit being, as hereinbefore stated,marking, spacing, marking, spacing and. spacing.v

Returning to the operation when the tion code signal corresponding toletter S is received and relay 3L responds first to the start pulse ofthe signal combination and then to the first selective pulse which ismarking, When relay 3L responds to the first selective pulse, itsarmature returns to the position shown. The armature of relay 3J is atthis timein engagement with its contact BJ and a circuit is closed fromground on the left-hand, or marking, contact and armature of relay 3L,resistance 32L armature and contact BJ of relay 3J, conductor 323, frontcontact and armature of relay 3A, condenser 3l0 to ground, to store azero potential on condenser 310.

When relay 3L responds to the second selective pulse, its armatureoperates to its righthand, or spacing, contact, the armature of relay 3Jat this time being in. engagement with its contact AJ and a circuit isclosed to store a -48 volt potential on condenser 3! I, the circuitbeing traceable from grounded 48 volt battery 324, spacing contact andarmature of relay 3L, resistance 32!, armature and contact AJ of relay3J, conductor 321', front. contact and upper armature of relay 3B,condenser 3 to ground.

When relay 3L responds to the third selective pulse, its armatureoperates to its left-hand, or marking, contact. The armature of relay 3Jat this time is in engagement with its contact BJ and a circuit isthereby closed from ground at the marking contact and armature of relay3L, resistance 32l, armature and contact BJ of relay 3.], conductor323-, front contact and upper armature of relay 3C, condenser M2 toround to store a zero potential on condenser 3 l 2.

When relay 3L responds to the fourth selective pulse, its armature againoperates to its spacing contact. The armature of relay 3J at this timeis in engagement with contact AJ and a circuit is thereby closed fromgrounded -48 volt battery 324 at the spacing contact and armature ofrelay 3L, resistance 32!, armature and contact AJ of relay 3J, conductor321, front contact and upper armature of relay 3D, condenser 353 toground to store a 48 volt potential on condenser 3l3.

When relay 3L responds to the fifth and last selective pulsev itsarmature remains on its spacing contact. The armature of relay 3J atthis time is in engagement with contact BJ nd a circuit is therebyclosed from grounded -48 volt battery 324 at the spacing contact andarmature of relay 3L, resistance 32!, armature and. contact BJ of relay3J, conductor 32!), front contact and upper winding of relay 3E,condenser 3M, to ground, to store a 48 volt potential on condenser 3M.

Relays 3A, 3B, 3C, 3D and 3E release, in turn, as hereinbefore describedso that the upper armatures thereof are moved into engagement with therespective back contacts. Relay 3M operates in response to the operationof relay 3F and the stored potentials on condensers are to 3 M areimpressed through armatures Nos. 1 to 5 of relay 3M, on conductors 328to 332, respectively. Conductors 328 to 332 may be multipled, as shown,to relays 3N and 3V and as many other relays as may be, used depending.on, the, number of permutathe desired function controlled. thereby,

combinations of resistances, such as resistances 333 to 331., that maybe employed.

Relay 3N which is assumed to be responsive to the transmission of thepermutation code signal combination corresponding to the letter S, ashereinbefore stated, is normally held in the position shown by currentflowing in a, circuit extending from grounded -es volt battery throughthe relay No. 2 winding, resistance 325 to ground. Conductors 328 and333 are connected through resistances 333 and 334, respectively, to apath extending through winding No. 1 of relay N to ground, andconductors 329, 33! and 332 are connected through, resistances 335, 333and 33?, re-. spectively, to a path extending through a resistance 326to ground. Therefore no current flows through the windings of relay 3Nas a result of the stored potentials on condensers 3H] to 3M. However,when relay 3M was inv released position during the time that thepermutation code signal corresponding to letter S was being received,condenser 325 was charged toa potential approximating the -48 voltpotential from grounded battery 338 and the relay, upon operating,impresses this stored potential on, a circuit extending over armatureNo. 6 and front contact of relay 3M, conductors 339 and 34!], throughthe No. 3 winding of relay 3N and to ground. Relay 3N momentarilyoperates to start the current flowing through winding No. 3 of relay 3Nbeing of such direction and magnitude to overcome the biasing current inwinding No. 2.

Fig. 6

The operation of the receiving unit shown in Fig. 3 can best beunderstood by reference to the curves shown in Fig. 6.

Curve 'lR shows the start-stop permutation code signal representingletter S that is assumed to be received over the signaling circuit andthen through the upper windings, in series, of" relays 3K and 3L. Ashereinbefore stated, the stop and start pulses arev marking and spacing,respectively, and the five selective pulses of the signal combinationare marking,

marking, spacing and spacing. Relays 3L and 3K spacing,

are normally in p'osition shown, that is, in their marking positionsunder the influence of the stop pulse current flowing in their upperwind; ings. Accordingly, during the idle interval of the receiving unit,condenser 333 is charged to a potential, approximating that of groundednegative l -volt battery 332, operated to the positions shown, relay 3Funder the control of its locking circuit which extends to ground atcontact AH and armature of relay 3H, and relay- 3M also under control ofrelay 3H.

Curve 2R shows the inductive action of the currents flowing in thewindings of relay 3K during the reception of a signal combination. Assoon as the start, or spacing pulse is received by relays ?L and 3K, thearmatures of both relays move to their respective spacing positionsunder the influence of the biasing currents flowing in their lowerwindings.

Relay 3K is maintained in a spacing position for the duration of thereception of a signal combination even though some of the selectivepulses of the signal combination received in the upper winding of relay3131 may be marking, as will be hereinafter described.

Curve 3R shows the operation, or position, of the armature. of relay 3Krelative to its marking and. spacing cont-acts, it being noted that thearmature remains on its spacing contact in response to the incomingstart pulse and the and relays 3F and 3M are 15 five selecting pulses,that is, for the duration of the signal combination regardless of thepolarity or nature of each individual selective pulse. Relay 3K, uponoperating, to its spacing contact, closes a discharging circuit forcondenser 303 which may be traced from ground, condenser 303, armatureand spacing contact of relay 3K, retardation coil 335, through thewindings, in parallel, of relays 3J, 3H and 3G, armature and contacts AGof relay 3G to ground. The discharge of condenser 303 operates thearmatures of relays 3J, 3H and 3G to their respectively associatedcontacts, BJ, BH and BG. Relay 3H, upon leaving its contacts AH, opensthe locking circuit of relay 3F which releases. Relay 3F, uponreleasing, effects at its upper armature and contact the release ofrelay 3M and at its outer lower armature and contact the closure of acircuit for shunting resistance 337 from the biasing circuit of relay3K. Relay 3K receives in its lower winding, when resistance 30'! isshunted, a biasing current of sufiicient magnitude to maintain itsarmature on its right-hand, or spacing contact, thereby producing theefiect of holding the relay in a spacing condition for the duration ofreception of the signal combination to which reference was hereinbeforemade. As soon as the armature of relay 3G engages its contacts BG,condenser 303 again charges to a negative potential of approximately 48volts in a circuit traceable from grounded negative battery 306,v

contact BG and armature of relay 3G, through the windings in parallel,of relays 3J, 3H and. 3G, retardation coil 305, right-hand, or spacingcontact and armature of relay 3K, condenser 303 to ground.

Curve 4R shows the nature of the current flowing in the windings, inparallel, of relays 3J, 3H and 3K of the oscillating circuit during eachoscillating interval beginning with the first closure of the armature ofrelay 3K with its spacing contact and ending with the reoperation ofrelay 3F immediately after the completion of the reception of a signalcombination. The cycles of the current due to the alternate charging anddischarging of condenser 303 recur in regular intervals.

Curve 5R shows the curve produced as the armature of relays 3J, 3H and3G engage their respective A and B contacts during the time condenser303 is charging and discharging in regular intervals. The relays operatesimultaneously and therefore their armatures will be on correspondingcontacts at the same instant.

Curve 6R shows the duration of the operation of each of relays 3A, 3B,3C, 3D and 3E during the time that a signal combination is beingreceived. Relays 3F and 3M which are normally operated, as hereinbeforestated, are in a release condition during the reception of these signalcombinations. These relays perform, as hereinbefore stated, the roughscanning process of the incoming signal combination and the refiningprocess is performed by relays 3J, 3H and 3G as part of the oscillatingcircuit. The cross-hatched section of each block representing theduration of operation of each of relays 3A, 3B, 3C, 3D and SE is theactual length of the corresponding pulse of the selective pulses thatare transmitted at the sending end of the signaling circuit, but eachis.

reproduced with respect to its corresponding pulse received by relays 3Kand 3L, to show a lag due to the time for energization and operation ofrelay 3K and the relays of the oscillating circuit.

: Curve IR shows the potential charge storedon during the time that thesignal combination is being received. Each of relays 3A, 3B, 3C, 3D

and 3E is in readiness to discharge the charge onits associatedcondenser at the time relay 3M reoperates in response to the reoperationof relay 3F, and these charges are simultaneously impressed overcharacter-recognizing circuit paths respectively including resistances333, 334, 335, 336 and 337. In response to a received signal combinationcorresponding to letter S the potential on each of condensers 3H] and3l2 will be zero and that on each of condensers 3| I, 3|3, 3M and 325will be negative 48 volts. The potential on condenser 325 is negative 48volts for each and every signal combination received. For a signalcombination of letter S, the charge on condenser 325 only is effectiveto operate the desired relay, such as relay 3N. Should any one or moreof the paths respectively controlled by relays 3A, 3B, 3C, 3D and 3Ecarry current, relay 3N would not have operated, inasmuch as itsoperation was not desired, but another relay, such as relay 3V, wouldhave responded.

If the character received over the signal circuit had not been S,current would have momentarily flowed in one or more of resistances 333to 33! which are preferably of different values and these currents wouldhave been of such direction and magnitude as to prevent the operation ofrelay 3N.

The scanning operation is completed at about the middle of the fifthselective pulse of the received permutation code signal. The operationof relay 3F restores the biasing current in the lower winding of relay3K to normal. If the fifth selective pulse is marking, relay 3K returnsto its marking contact M, immediately. If the pulse is spacing, relay 3Kreturns to its marking contact M at the beginning of the stop pulse. Thereturn of the armature of relay 3K to its marking contact M stops theoscillating circuit and prepares it for restarting upon the receipt ofthe next incoming permutation code signal.

It is not necessary to limit this circuit to sending open and closedsignals. For example, minor alterations would permit it to apply to theoutgoing line alternate positive and negative battery or alternatebattery and ground.

Two rotary stepping selector switches may be used to perform the roughscanning of relays 2A, 2B, 2C, 2D, 2E, 2F, station. One selector switchoperated from the BK contact of relay 2K can perform the function ofrelays 2A, 2C, 2D and 2G, and another selector switch operated fromcontact AK of relay 2K can perform the functions of relays 23, 2D, 2Fand 2H.

What is claimed is:

1. In a, distributor, a start element, a chain of stepping relays, atimed vibrating element, conductive means to which code pulsesrepresenting marking and spacing conditions are to be deliveredsequentially, a source of pulses to be distributed, a pulse refining ortiming relay, means whereby the start element initiates the operation ofthe vibrating element, means whereby the refining relay follows thevibrating element, means whereby the vibrating element controls thestepping of the chain of stepping relays, and paths closed in successionto said conductive means, each-said path including a, closed path over acontact from a source determined as marking or spacing by a codecondition and including a 2G and 2H at the sending refining relay.

2. In a distributor system, a start element, a

chain of stepping relays, a timed vibrating element, a device forsetting up permutated marking and spacing conditions for controllingpulses to be delivered sequentially to a transmission conductor, a pulserefining or timing relay, means whereby the start element initiates theoperation of the vibrating element, means operable incident to the startof operation of the vibrating element to transmit a start pulse to saidconductor preceding the pulses to be distributed, means whereby therefining relay follows the vibrating element, means whereby thevibrating element control-s the stepping of the chain of stepping relaysand paths closed in succession to said transmission conductor, each saidpath including a closed path over a contact from a source determined asmarking or spacing by said device and including a contact of a steppingrelay and a contact of said refining relay.

3. In an arrangement according to claim 2, means operable incident toand following the transmission of the last code pulse of a code group tosaid transmission conductor to restore said transmission conductor tomarking condition.

4. A distributor for distributing a group of mixed marking and spacingconditions comprising a chain of stepping relays and a refining relay, aconductor to which said conditions are to be distributed, means forclosing in series a plurality of paths one for each element of saidgroup of conditions each of which paths includes a contact of adifferent stepping relay and a contact of said refining relay.

5. Means for distributing groups of code pulses of the start-stop typein which each group includes a start pulse and a sequence of mixedmarking and spacing conditions, comprising an element for receiving saidconditions from an incoming line, start means, a vibratory timingelement, a refining element and a relay chain in which the start pulseinitiates the operation of said vibratory timing element and controlsthe stepping chain and in which means are provided to cause the refiningelement to follow the vibratory element, also including devices innumber equal to the number of code conditions, means whereby each suchdevice is successively included in a path over a contact of a steppingelement and a contact of said refining element.

6. A selective system operable by permutation codes in which each codeelement may comprise either of two conditions and the total number ofcode elements in a group is 1 Comprising n capacity elements and amaximum number of Z elements to be selectively controlled, means fordistributing a code group of 11 conditions to said capacity elements tocharge them individually according to the nature of the individual codeelement conditions, means for discharging said capacity elementssimultaneously to said elements to be controlled and conductiveconnections to said controlled elements whereby one thereof may beoperated or conditioned selectively out of the entire group upon eachdischarging operation.

7. In a relay distributor system, a vibratory relay, a start relay, arefining relay, a relay chain, means whereby the vibratory relaycontrols the start relay and the refining relay, means whereby the startrelay initiates operation of the relay chain, means for closing insuccession paths including contacts of the refining relay andsuccessively closed paths over the contacts of the relays of the relaychain, selector means comprising a series of storage elements equal to agiven number n, a maximum of 2 elements to be controlled,interconnecting means between said storage elements and elements to becontrolled whereby simultaneous discharge of all said elements throughsaid elements to be controlled selectively operates one of the entirenumber thereof.

WILLIAM R. YOUNG, JR.

